TORONTO (miningweekly.com) – TSX- and NYSE-listed Nevsun Resources, which is focused on extracting copper from its 60%-owned high-grade Bisha copper mine, in Eritrea, on Tuesday announced a 29% rise in total indicated mineral resources, last estimated on May 31, 2012.

The resource estimate was boosted by the maiden openpit resource estimates for the Hambok and Northwest zone deposits and the updated mineral reserve estimates for the Bisha main and Harena openpit mines. Hambok and the Northwest zone are satellite deposits to the Bisha main pit and, in addition to Harena, were expected to provide additional feed to the Bisha mill, extending the mine life.

Nevsun said that the combined property tenements its subsidiary Bisha Mining Share Company controls had added 9.3-million combined oxide gold, supergene copper and primary copper/zinc zone tonnes.

This resulted in in-situ copper rising by 22%, or 247-million pounds, and in-situ zinc rising 1%, or 47-million pounds.

Using a net smelter return cutoff of $39.55/t at $2.90/lb for copper and $0.92/lb for zinc, the updated Bisha main pit probable mineral reserve estimate consisted of supergene copper ore of 7.4-million tonnes grading at 3.57% copper, 0.61 g/t gold and 27 g/t silver and primary copper/zinc ore of 18.4-million tonnes grading at 1.02% copper, 5.66% zinc, 0.68 g/t gold and 46 g/t silver.

"Despite mining depletion and cost inflation since our last reserve report in mid-2012, Bisha base metal mine life is 11 years, demonstrating the robust nature of the high-grade Bisha main orebody,” Nevsun CEO Cliff Davis said.

The maiden openpit Hambok indicated mineral resource estimate included 6.9-million tonnes grading at 1.14% copper and 1.86% zinc for 172-million pounds copper and 281-million pounds zinc.

The maiden openpit Northwest zone indicated resource estimate included one-million tonnes of supergene material grading 1.47% copper and 2.5-million tonnes of primary material grading at 1.04% copper and 1.08% zinc for a combined 92-million pounds copper and 60-million pounds zinc.

"The addition of new resources at Hambok and the Northwest zone is an exciting first step to expanding the resource base at Bisha. All four Bisha deposits are open with extensions that we have yet to define. We also look forward to further exploration success and unlocking the potential in the Bisha VMS camp,” Davis said.